The invention relates to a method for obtaining information regarding at least one target through the transmission of radar transmitter pulses and the subsequent processing, in a receiver and in a processor, of target echoes obtained in the listening intervals between radar transmitter pulses, for observing the target with a predetermined range resolution, in which process K bursts of radar transmitter pulses are transmitted, a different radar transmit frequency is selected for each burst and moreover, within a burst, groups of pulses with N mutually different transmit frequencies are transmitted repeatedly for the purpose of Doppler processing, so that per transmission, K.N. different radar transmit frequencies are transmitted to achieve the selected range resolution.
More specifically, the method is aimed at obtaining target information with an extremely high range resolution and a Doppler processing that is of a sufficient quality to distinguish the generally moving target from the generally stationary background. A method of this type is known from EP 0.706.061 A2. The method described in this patent specification renders a high range resolution and a good Doppler processing possible for a radar having a limited instantaneous bandwidth. According to the known method, pulses are transmitted at recurrent intervals, as is usual in radar engineering, whereupon the echoes from a transmitted pulse are received in a listening interval. This implies that a target has to be illuminated for a relatively long time, as the high range resolution is achieved by processing the echoes of a complete radar transmission. This is a time-consuming process for the radar apparatus, which usually operates multifunctionally and is therefore during that time unavailable for other tasks. Moreover, a long illumination time increases the risk of interference, for instance caused by jamming signals or a deviation of the target trajectory.